Help Jonathan Kay

My wifes friend has a new Dell, window messenger and MSN
messenger, both the latest version. I have the same on
mine PC. On windows messenger, trying to establish a
video call, she can see and hear me, I see myself but do
not see or hear her. I had her turn off her XP firewall
and disable the QoS per earlier messages I read from you,
I turned off my norton and XP firewall, same results.
Even took out and purchase a new cisco linksys 4 port
router thinking this may be the problem, still the same.
Took my wifes pc over to her friend, turned off the XP
and norton firewall, neither one of us could see or hear
the other. We then went to netmeeting, worked great.
Took her camera and put on her friends, still the same as
before on messenger. She could see and hear me, my PIP
worked, couldn't see or hear her.
Went to MSN. Could see each other if we both called the
other party on webcam, nothing worked on establish video
call, could not get audio on either.

Help, we have spent many hours trying all combination of
hardware and software, read your replys to others, still
can't fix.

Thanks